Photographic color developer solution stabilized with lithium ions

ABSTRACT

WHEREIN R is a lower alkyl radical having from one to five carbon atoms, inhibits the formation of the white precipitate characteristically produced when sequestrants of this type are used to sequester ions of heavy metals such as calcium. Alkali metal, ammonium and ethanolamine salts of compounds of the above formula and mono and dialkyl esters thereof with methanol, ethanol, propanol and butanol also provide useful sequestering agents.   The incorporation of small amounts of lithium ion into a solution of a heavy metal sequestering agent of the formula:

United States Patent [191 Brown Oct. 1, 1974 IONS [75] Inventor: JesseL. Brown, Rochester, NY. [73] Assignee: Eastman Kodak Company, 4Rochester, NY. [22] Filed: June 8, 1973 [211 App]. No.: 368,167

Related US. Application Data [62] Division of Ser. No. 224,627, Feb. 8,1972, Pat. No.

[52] US. Cl. 96/66.4, 96/66 R [51] Int. Cl G03c 5/30 [58] Field ofSearch 96/66, 66.4

[56] References Cited UNITED STATES PATENTS 2,541,470 2/1951 Henn96/66.4 3,201,246 8/1965 Allen et al. 96/66.4 3,647,449 3/1972 Malloy96/66 R 3,746,544 7/1973 Heilmann 96/66.4

Primary Examiner-Mary F. Kelley Attorney, Agent, or Firm-A. P. Lorenzo[57] ABSTRACT The incorporation of small amounts of lithium ion into asolution of a heavy metal sequestering agent of the formula:

wherein R is a lower alkyl radical having from one to five carbon atoms,inhibits the formation of the white precipitate characteristicallyproduced when sequestrants of this type are used to sequester ions ofheavy metals such as calcium. Alkali metal, ammonium and ethanolaminesalts of compounds of the above formula and mono and dialkyl estersthereof with methanol, ethanol, propane] and butane] also provide usefulsequestering agents.

13 Claims, No Drawings PHOTOGRAPHIC COLOR DEVELOPER SOLUTION STABILIZEDWITH LITHIUM IONS This is a division of application Ser. No. 224,627filed Feb. 8, 1972, and issued Feb. 26, 1974, as U.S. Pat. No.3,794,591.

FIELD OF THE INVENTION The present invention relates to improved methodsfor sequestering heavy metal ions and in particular to photographicdeveloper solutions which contain such heavy metal ion sequesteringagents and small amounts of lithium.

BACKGROUND OF THE INVENTION U.S. Pat. No. 3,214,454 to Blaser et al.,issued Oct. 26, 1965 describes the preparation of organic acylationproducts of phosphorous acid and particularly compounds of the formula:

.SBE.. ...I ...-.E...

wherein R is a lower alkyl group having from one to five carbon atomsand the use of these materials as complex formers (sequestering agents)for metal ions and particularly polyvalent metal ions.

The utility of these compounds as sequestering agents and theirexceptional abilities as complex formers of heavy metal ions is wellknown by those skilled in this art. However, these materials do have atleast one relatively major shortcoming. This shortcoming is clearlymanifested when compounds of the class described are used to sequester,for example, calcium from an alkaline solution which also contains, forexample, sodium or potassium ion. In such a sytem a characteristic whiteprecipitate, which is readily recognized by the skilled artisans in thisfield, forms after a very short period of time.

Im many usages, and in particular in photographic development, thisprecipitate can produce deleterious effects some of which are similar tothose which prompted addition of the sequestrant initially.

OBJECTS OF THE INVENTION It is therefore an object of the presentinvention to provide a method of sequestering, for example, calcium ionfrom a solution using the aforementioned acylation.

SUMMARY OF THE INVENTION According to the present invention, theformation of a white precipitate when an organic acylation product ofphosphorus acid and in particular compounds of the formula n o lIOI 4JI0H dn II on wherein R is a lower alkyl group having from one to fivecarbon atoms, is used to sequester heavy metal ions, especially calcium,is inhibited by the addition of small amounts of lithium ion to thesequestering agent solution.

DETAILED DESCRIPTION OF THE INVENTION In a solution containing alkalimetal ions other than lithium, for example, sodium and potassium ions aswell as polyvalent metal ions, attempts to sequester the polyvalentmetal ions with organic acylation products of the type described aboveand in U.S. Pat. No. 3,214,454 have resulted in the formation of a whiteprecipitate. It has now been discovered that the incorporation of atleast about ppm of lithium ion in such a solution inhibits the formationof such a white precipitate. I

These acylation products can be produced, e.g., by reacting phosphorousacid with acid anhydrides and/or acid chlorides, especially those ofacetic, propionic, butyric, valeric and caproic acid. When both theanhydride and the chloride are used simultaneously, they must be derivedfrom the same acid, e.g., the anhydride and the chloride of acetic acidcan be used simultaneously, but not acetic anhydride together withpropionic chloride. In lieu of phosphorous acid and one of the acidchlorides named above, phosphorus trichloride can be reacted with one ofthe carboxylic acids themselves. Particularly readily available are thereaction products of phosphorous acid with acetic anhydride, with acetylchloride or with a mixture thereof. The reactions opportunely arecarried out at elevated temperatures, preferably between and 200C.

As described in the aforementioned U.S. Pat. No. I

3,214,454 the concentration of sequestering agent may range from 1 molper 5000 mols of metal up to stoichiometric quantities of sequesteringagent and polyvalent metal ion.

According to a preferred embodiment of the present invention wherein theorganic acylation product of phosphorous acid is used as a sequesteringagent in a photographic developer the concentration of lithium ionranges between about 100 and 450 ppm. Below this range insufficientlithium is present to inhibit precipitate formation while atconcentrations substantially above this range undesirable sensitometriceffects occur which make use of such levels of lithium in a photographicenvironment practically impossible.

In solutions of sequestering agents of the type described above, whichsolutions are used in an environment other than that of a photographicdeveloper, the effective upper limit of lithium ion concentration can begoverned by one or more of the following factors:

(1) tolerance of the solution for lithium ion; (2) the upper limit ofsolubility of the source of lithium ion in the particular solution; and(3) perhaps in some cases toxicity levels of lithium compounds whichmight to some degree limit their use.

The lithium ion can be supplied to the solution of sequestering agent inany suitable form. This generally will be as a soluble salt of lithium.for example as lith ium sulfate, lithium sulfite. lithium hydroxide,etc. In photographic developer compositions which have very sensitivebalances of a variety of ions for example, sulfite, sulfate, buffer(i.e. borate, carbonate, etc.) and halogen ion it is generally advisableto add the lithium as a salt whose anion is common to the system andcompatible therewith. For example, when a carbonate buffer is used insuch a system, the lithium is advantageously added as lithium carbonate.In a developer which contains a sequestering agent of the type describedand a borate buffer the lithium is advantageously added as lithiumhydroxide. Similarly lithium sulfate is preferred when the developercontains hydroxylamine sulfate. Since it is generally advisable tomaintain a low halogen ion concentration in photographic developers, theaddition of lithium as lithium chloride, bromide or iodide generallyproduces undesirable sensitometric effects, however, in othersequestering mediums where halogen ion content produces no adverseeffect lithium ion can be provided in the form of a halogen salt.

Although the concentration of lithium in the sequestering bath may varybroadly within the limits described above, superior results are achievedwhen the ratio of lithium ion to other alkali metal ions in the solutionranges from about 0.5 to 1.5 1. At this level of lithium ionsubstantially complete freedom from undesirable precipitate is noted.

Similarly, although the improved results of the instant invention areachieved when almost any polyvalent metal ion is being sequestered (forexample, Mg Ca Cu Zn +2 and Fe the most obvious improvement is obtainedin solutions used to sequester calcium in (Ca since it is in this mediumthat the most aggravated precipitation occurs, particularly in thephotographic field where sequestering agents of this type are used asanti-calcium agents.

Although applicant does not wish to be bound by any particular theoryfor the mechanism of his invention it is believed that in solutionscontaining polyvalent metal ions, (Ca Cu etc.) a sequestering agent ofthe type described and alkali metal ions other than lithium, forexample, sodium and/or potassium the dialkali, monopolyvalent ion saltof the sequestering agent is formed and it is this species whichprecipitates. Thus, where the solution contains sodium and calcium ion,the disodium, monocalcium salt of the sequestering agent would form theprecipitate. In the case where both sodium and potassium were present inthe solution the precipitate formed could be the disodium, dipotassiumor monosodium, monopotassium, monocalcium salt of the sequesteringagent, etc.

From this, or any other theory for the formation of the precipitate, itseems very surprising that the addition of further amounts of an alkalimetal ion, namely lithium, would provide any beneficial effect let alonethe elimination of the precipitate which presumably includes alkalimetal ion.

The following examples will serve to demonstrate the invention describedherein.

EXAMPLE 1 A photographic developer solution having the followingcomposition Hydroxylamine sulfate I 4.5 gm

Sodium Hydroxide (50 80 gm Benzyl alcohol 15.7 ml

-Continued Potassium hydroxide 51 gm sodium sulfite 1.9 gm Boric acid19.0 gm 4-amino-N-ethyl-N[B-methanesulfonamidoethyll-m-toluidine(sequisulfate monohydrate) 5.3 gm Sufficient water to make 1 liter wasprepared and utilized to develop imagewise exposed, silver coupler colorprint material. To this seasoned solution were added the amounts ofcalcium ion, and organic phosphorous acid sequestering agent, indicatedin Table 1 below.

TABLE I Cad-l- 60% aqueous solution Results after 38 days ofsequestering Agent 350 ppm 2 mill Precipitate 300 ppm 2 ml/l Precipitate250 ppm 2 ml/l Precipitatc 200 ppm 2 ml/l Precipitate 150 ppm 2 ml/lPrecipitate Thus, precipitate formed at all of these levels ofCa-l-iwhen the organic phosphorous acid derivative was used assequestrant.

EXAMPLE 2 The method of Example 1 was repeated except that the additionto the seasoned developer comprised:

0.25 M K CO l ml/l 60 percent aqueous solution of sequestering agent*and ppm Ca-H- In addition to the foregoing the additions shown in TableII were incorporated into the seasoned developer and the resultsindicated.

TABLE II Additive Result Standard (no further additive) Precipitate (3days) 1 g/l potassium hexametaphosphate Precipitate (3 days) 0.05 M Li+No precipitate 0.05 M Rb+ Precipitate (3 days) 0.05 M Cs+ Precipitate (3days) EXAMPLE 3 An aqueous solution comprising 0.25 M K CO l ml/l of a60 percent aqueous solution of organic phosphorous acid sequesteringagent* and 100 ppm of Ca-H- was prepared. To this solution the additionsindicated in Table III were made. The approximate weight of precipitateformed after 10 and 17 days is shown in Table 111.

5. lithium ions in a concentration sufficient to substantlally preventformation in said solution of a precipitate of said sequestering agent.

2. A solution as claimed in claim 1 wherein said seused as sequesteringagent 5 questering agent is present in said solution in an amount offrom about 1 mole per 5000 moles of poly- EXAMPLE 4 valent metal ion upto stoichiometric quantities based The following Table IV gives the time(in days) until 0n the total polyvalent metal ion concentration and thei bl precipitate f -m d i an aqueous 025 M concentration of lithium ionsin said solution is at least K CO solution containing 1 ml/l of a 60percent aqueabout pmous solution of l-hydroxyethylidene-l,l-diphosphonic 3. A solution as claimed in claim 1 wherein saidpolyacid. W V valent metal ions are calcium ions.

TABLE IV Na Concentration 0.2 M 0.1 M 0.04 M 0.02 M

Ca Cone. (ppm) 100 200 100 200 100 200 I00 200 Li Conc.

0.l M 48 days 0.04 M 13 days days 48 days 48 days 0.02 M 13 days 20 days20 days 48 days 0.00 M 1 day 7 days 68 days From the foregoing Example4, it should be clear that 4. A solution as claimed in claim 1 whereinsaid alkali highest stability (ie., resistance to precipitation) forsometal 1008 a SOdlutn Ions. lutions containing calcium is achieved whenthe weight Asolutlon as clalfned l" 1 Where!" Said alkali ratio oflithium ion to other alkali metal ions is at least metal lons fPOtaSSIPm F about 0.02:1. Further improved results are achieved A,Solutlon dammed g l l when this ratio is at least about 0.05:1 andoptimum reqpestermg a e cqmpoun o t m? sults are achieved at the levelwhere this ratio is at least about 0.1:1 The upper limit of this ratiowill depend to i a large extent upon the concentration and solution tol-HOP --POH erance factors described above. Thus, no absolute OH 6 upperlimit can be described, however, as a practical 3 5 matter, lithium toother alkali metal ion ratios above m 1031 would appear Serve no usefulP f 7. A solution as claimed in claim 1 wherein the conpamcularlyPhotographlc developer composltlonscentration of said lithium ions isfrom about lOO ppm The invention has been described in detail with partoabout 450 ppm ticular reference to the preferred embodiments 40 ASolution as claimed in claim 1 wherein the b be understood h 9' andweight ratio of said lithium ions to said alkali metal ionsmodifications can be effected within the spirit and is at least about 002 to 1 Scope 9 the mvemlon- 9. A solution as claimed in claim 1 whereinthe I clam: weight ratio of said lithium ions to said alkali metalions 1. An aqueous alkaline photographic color developer i at leastabout (105 to 1 sohmon compnsmg, 10. A solution as claimed in claim 1wherein the a Color developmg agent weight ratio of said lithium ions tosaid alkali metal ions Polyvalent fnetal 1on5 is in the rangefrom about0.5:1 to about l 5:l.

a ,sequestefmgagem for sald, polyvalem metal lens 11. A solution asclaimed in claim 1 additionally con- Sald q f agent bemg Selected fromthe taining hydroxylamine sulfate, sulfite ion and benzyl groupconsisting of i i V V I Phosphorus. Compounds Ofthe l 12. A solution asclaimed in claim 1 wherein said color developing agent is4-amino-N-ethyl-N-(B- 0 R methanesulfonamidoethyl)-m-toluidinesesquisulfate o i monohydrate.

6 H 13. An aqueous alkaline photographic color developer solutioncomprising l. a color developing agent, lltlgerrltsa R 15 an alkyl groupof from one to five carbon 2. Calcium ions 0 3. a sufficient amount ofl-hydroxyethylidene-l,lb. alkali metal, ammonium and ethanolamme saltsdiphosphonic acid to sequester Said calcium ions of said phosphoruscompounds, and 4 S dium r otasshm ion t bl f c. monoalkyl and dialkylesters of said phosphorus o f S m g q i compounds with methanol,ethanol, propanol or mg m h orma a 'P' o e butanol, -h) 'droxyety1dene-l, l-diphosphonic acid, a ntlll 4. alkali metal ions selectedfrom the group consistmm 10mm an amount suffic'em to Substama y ing ofsodium ions and potassium ions in a concentration capable of resultingin the formation of a precipitate of said sequestering agent, and

prevent the formation of a precipitate of the l-hydroxyethylidene-ll-diphosphonic acid.

1. A COLOR DEVELOPING AGENT,
 1. AN AQUEOUS ALKALINE PHOTOGRAPHIC COLORDEVELOPER SOLUTION COMPRISING
 2. polyvalent metal ions,
 2. POLYVALENTMETAL IONS,
 2. calcium ions,
 2. A solution as claimed in claim 1 whereinsaid sequestering agent is present in said solution in an amount of fromabout 1 mole per 5000 moles of polyvalent metal ion up to stoichiometricquantIties based on the total polyvalent metal ion concentration and theconcentration of lithium ions in said solution is at least about 100ppm.
 3. a sufficient amount of 1-hydroxyethylidene-1,1-diphosphonic acidto sequester said calcium ions,
 3. A SEQUESTERING AGENT FOR SAIDPOLYVALENT METAL IONS, SAID SEQUESTERING AGENT BEING SELECTED FROM THEGROUP CONSISTING OF A. PHOSPHORUS COMPOUNDS OF THE FORMULA
 3. A solutionas claimed in claim 1 wherein said polyvalent metal ions are calciumions.
 3. a sequestering agent for said polyvalent metal ions, saidsequestering agent being selected from the group consisting of a.phosphorus compounds of the formula
 4. ALKALI METAL IONS SELECTED FROMTHE GROUP CONSISTING OF SODIUM IONS AND POTASSIUM IONS IN ACONCENTRATION CAPABLE OF RESULTING IN THE FORMATION OF A PRECIPITATE OFSAID SEQUESTERING AGENT, AND
 4. sodium or potassium ions in an amountcapable of resulting in the formation of a precipitate of the1-hydroxyethylidene-1, 1-diphosphonic acid, and
 4. alkali metal ionsselected from the group consisting of sodium ions and potassium ions ina concentration capable of resulting in the formation of a precipitateof said sequestering agent, and
 4. A solution as claimed in claim 1wherein said alkali metal ions are sodium ions.
 5. A solution as claimedin claim 1 wherein said alkali metal ions are potassium ions.
 5. lithiumions in a concentration sufficient to substantially prevent formation insaid solution of a precipitate of said sequestering agent.
 5. lithiumions in an amount sufficient to substantially prevent the formation of aprecipitate of the 1-hydroxyethylidene-1, 1-diphosphonic acid. 5.LITHIUM IONS IN A CONCENTRATION SUFFICIENT TO SUBSTANTIALLY PREVENTFORMATION IN SAID SOLUTION OF A PRECIPITATE OF SAID SEQUESTERING AGENT.6. A solution as claimed in claim 1 wherein said sequestering agent isthe compound of the formula:
 7. A solution as claimed in claim 1 whereinthe concentration of said lithium ions is from about 100 ppm to about450 ppm.
 8. A solution as claimed in claim 1 wherein the weight ratio ofsaid lithium ions to said alkali metal ions is at least about 0.02 to 1.9. A solution as claimed in claim 1 wherein the weight ratio of saidlithium ions to said alkali metal ions is at least about 0.05 to
 1. 10.A solution as claimed in claim 1 wherein the weight ratio of saidlithium ions to said alkali metal ions is in the range from about 0.5:1to about 1.5:1.
 11. A solution as claimed in claim 1 additionallycontaining hydroxylamine sulfate, sulfite ion and benzyl alcohol.
 12. Asolution as claimed in claim 1 wherein said color developing agent is4-amino-N-ethyl-N-( Beta -methanesulfonamidoethyl)-m-toluidinesesquisulfate monohydrate.
 13. An aqueous alkaline photographic colordeveloper solution comprising